* Thigh has three fascial compartments
1. Anterior
2. Medial
3. Posterior
* The Anterior compartment of the thigh includes muscles such as
- Vastus medialis (V M)
- Vastus intermedius (V I)
- Vastus lateralis (V L)
- Rectus femoris (R F)
- Sartorius (S)
* The Medial compartment includes muscles such as
- Adductor magnus
- Adductor longus
- Gracilis
- Adductor brevis (not seen here because it terminates a little higher)
* The posteior compartment of the thigh includes muscles such as
- Semimebranosus
- Semitendinosus
- Biceps femoris (both long and short heads)
Like any suture of the skull which joins two bones, this squamous suture; sometimes also called as the squamosal suture joins the parietal bone to the temporal bone (the temporal bone has two parts - the petrosal part and the squamous part - this suture joins the squamous part of the temporal bone to the parietal bone).
It is oriented horizontally and extends posteriorly from the pterion (Pterion is the region as indicated in the figure above, that is the meeting point of the frontal, parietal, temporal and sphenoid bones). The suture continues posteriorly as the petromastoid suture.
Some consider the posterior part the squamous suture as a separate suture called additamentum posterius suturae squamosae because of its serrated appearances in most of the humans.
*Thoracic lymph nodes are classified into 14 stations:
*Station number 1 : Low cervical, Supraclavicular and Sternal notch nodes.(R and L).
*Station number 2 : Upper paratracheal nodes (R and L).
*Station number 3 : Prevascular(3a) and Retrotracheal nodes (3p).
*Station number 4 : Lower paratracheal nodes (R and L).
*Station number 5 : Subaortic (aortopulmonary window).
*Station number 6 : Paraaortic (ascending aorta or diaphragm).
*Station number 7 : Subcarinal nodes (R and L).
*Station number 8 : Paraesophageal (below carina) nodes (Right and Left).
*Station number 9 : Pulmonary ligament nodes
*Station number 10,11,12,13,14 : Hilar(Right and Left), Interlobar(11s and 11i), Lobar, Segmental and Subsegmental.
- Stations 10,11,12,13,14 , when involved are considered stage N1 disease of lung cancer.
- Ipsilateral Mediastinal nodes involvement : Stations 2,3,4 and 7,8,9 - Stage N2 disease of lung cancer.
- Lymph nodes on the side opposite the primary tumor, and all significantly large lymph nodes in the ipsilateral or contralateral supraclavicular or scalene regions, are considered stage N3 disease.
The sciatic nerve (also known as the ischiadic nerve and the ischiatic nerve) is a large nerve in humans.
It begins in the lower back and runs through the buttock and down the lower limb.
It is the longest and widest single nerve in the human body going from the top of the leg to the foot on the posterior aspect.
The sciatic supplies nearly the whole of the skin of the leg, the muscles of the back of the thigh, and those of the leg and foot.
It is derived from spinal nerves L4 through S3.
It contains fibres from both the anterior and posterior divisions of the lumbosacral plexus.
The nerve gives off articular and muscular branches:
The articular branches (rami articulares) arise from the upper part of the nerve and supply the hip-joint, perforating the posterior part of its capsule; they are sometimes derived from the sacral plexus.
The muscular branches (rami musculares) are distributed to the following muscles of the lower limb: biceps femoris, semitendinosus, semimembranosus, and the hamstring portion of adductor magnus.
The nerve to the short head of the biceps femoris comes from the common fibular part of the sciatic, while the other muscular branches arise from the tibial portion, as may be seen in those cases where there is a high division of the sciatic nerve.
The muscular branch eventually gives off the tibial nerve and common fibular nerve, which innervates the muscles of the (lower) leg.
The tibial nerve goes on to innervate all muscles of the foot except the extensor digitorum brevis (which is innervated by the common fibular nerve).
The sciatic nerve innervates the skin on the posterior aspect of the thigh and gluteal regions, as well as the entire lower leg (except for its medial aspect).
Pain caused by a compression or irritation of the sciatic nerve by a problem in the lower back is called sciatica.
Common causes of sciatica include the following lower back and hip conditions: spinal disc herniation, degenerative disc disease, lumbar spinal stenosis, spondylolisthesis, and piriformis syndrome.
Other acute causes of sciatica include coughing, muscular hypertension, and sneezing.
Sciatic nerve injury occurs between 0.5% and 2.0% of the time during total hip arthroplasty. Sciatic nerve palsy is a complication of total hip arthroplasty with an incidence of 0.2% to 2.8% of the time, or with an incidence of 1.7% to 7.6% following revision.
Following the procedure, in rare cases, a screw, broken piece of trochanteric wire, fragment of methyl methacrylate bone cement, or Burch-Schneider metal cage can impinge on the nerve; this can cause sciatic nerve palsy which may resolve after the fragment is removed and the nerve freed.
The nerve can be surrounded in oxidized regenerated cellulose to prevent further scarring.
Sciatic nerve palsy can also result from severe spinal stenosis following the procedure, which can be addressed by spinal decompression surgery.
Bernese periacetabular osteotomy resulted in major nerve deficits in the sciatic or femoral nerves in 2.1% of 1760 patients, of whom approximately half experienced complete recovery within a mean of 5.5 months.
Sciatic nerve exploration can be done by endoscopy in a minimally invasive procedure to assess lesions of the nerve.
Endoscopic treatment for sciatic nerve entrapment has been investigated in deep gluteal syndrome; "Patients were treated with sciatic nerve decompression by resection of fibrovascular scar bands, piriformis tendon release, obturator internus, or quadratus femoris or by hamstring tendon scarring."
The transverse foramen (Latin: foramen transversarium) pierces the transverse processes of the seven cervical vertebrae. In the upper six vertebrae, the foramen gives passage to the vertebral artery, vertebral vein, and a plexus of sympathetic nerves. The seventh foramen lacks the artery, but contains the vein and sympathetic nerves.
The superior mesenteric artery supplies the caecum, appendix, ascending colon and right two-thirds of the transverse colon via the ileocolic, right colic and middle colic branches. The ileocolic artery is formed as the distal continuation of the superior mesenteric artery in the root of the small bowel mesentery after the origin of the last ileal artery.
The inferior mesenteric artery is usually smaller in calibre than the superior mesenteric artery, and arises from the anterior or left anterolateral aspect of the aorta at about the level of the third lumbar vertebra, 3 or 4 cm above the aortic bifurcation and posterior to the horizontal part of the duodenum. It descends deep to the peritoneum, initially anterior and then to the left of the aorta. It crosses the origin of the left common iliac artery medial to the left ureter and then enters, and continues in, the root of the sigmoid mesocolon as the superior rectal artery. Distally the inferior mesenteric vein is lateral to it. The principal branches are the left colic, sigmoid (of which there may be several) and superior rectal artery.
The arc of Riolan (AOR) is also known as the meandering mesenteric artery or central anastomotic mesenteric artery.
It is an inconstant artery that connects the proximal superior mesenteric artery (SMA) or one of its primary branches to the proximal inferior mesenteric artery (IMA) or one of its primary branches. It is classically described as connecting the middle colic branch of the SMA with the left colic branch of the IMA. It forms a short loop that runs close to the root of the mesentery.
When present, the AOR is an important connection between the SMA and IMA in the setting of arterial occlusion or significant stenosis. In proximal SMA occlusion, the AOR provides collateral flow from the IMA to the SMA territory. In proximal IMA occlusion, it provides collateral flow from the SMA to the IMA territory. In distal abdominal aortic occlusion it provides collateral flow from SMA to IMA to iliac vessels (via the superior rectal artery) and then to the lower limbs (via the external iliac artery).
*I am not gonna explain the entire anatomy of the knee here, coz u will find that in hundreds of books. I am gonna post a video made by Dr. Bertram Zarins of the Mass General Hospital Sports Medicine Service, which has made me happy (happy because of its simplicity and beauty in explaining the basic anatomy). Sometimes you try explaining hundreds of things to students without a picture or video and they dont get it, but u show them a beautiful video or picture and they dont need you. This is one of those videos. Point to note is that the doctor was trying to explain Anterior cruciate ligament repair here and not anatomy.
Things to understand from this video :
1. The Anterior cruciate ligament ACLoriginates from deep within the notch of the distal femur. Its proximal fibers fan out along the medial wall of the lateral femoral condyle. There are two bundles of the ACL—the anteromedial and the posterolateral, named according to where the bundles insert into the tibial plateau. The ACL attaches in front of the intercondyloid eminence of the tibia, being blended with the anterior horn of the medial meniscus. These attachments allow it to resist anterior translation and medial rotation of the tibia, in relation to the femur.
2.The posterior cruciate ligament (or PCL) is one of the four major ligaments of the knee. It connects the posterior intercondylar area of the tibia to the medial condyle of the femur. This configuration allows the PCL to resist forces pushing the tibia posteriorly relative to the femur.
3. Medial collateral ligament : It is a broad, flat, membranous band, situated slightly posterior on the medial side of the knee joint. It is attached proximally to the medial condyle of femur immediately below the adductor tubercle; below to the medial condyle of the tibia and medial surface of its body. It resists forces that would push the knee medially, which would otherwise produce valgus deformity.
4. Lateral collateral ligament : Rounded, more narrow and less broad than the medial collateral ligament, the fibular collateral ligament stretches obliquely downward and backward from the lateral epicondyle of the femur above, to the head of the fibula below. In contrast to the medial collateral ligament, it is fused with neither the capsular ligament nor the lateral meniscus. Because of this, the lateral collateral ligament is more flexible than its medial counterpart, and is therefore less susceptible to injury.The fibers of the posterior part of the ligament are short and incline backward as they descend; they are inserted into the tibia above the groove for the semimembranosus muscle.The anterior part of the ligament is a flattened band, about 10 centimeters long, which inclines forward as it descends.It is inserted into the medial surface of the body of the tibia about 2.5 centimeters below the level of the condyle. It resists forces that would push the knee laterally, which would otherwise produce a varus deformity. *Other important structures related to knee anatomy are the menisci of the knee and the bursa surrounding the knee, which i am gonna discuss in another post someday.
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Now try answering these Multiple choice questions (mcqs): 1.Posterior Cruciate ligament prevents a.Anterior movement of tibia in relation to femur b.Posterior movement of tibia in relation to femur c.Medial movement of tibia d.Lateral movement of tibia
2.Anterior cruciate ligament prevents a.Anterior movement of tibia in relation to femur b.Posterior movement of tibia in relation to femur c.Medial movement of tibia d.Lateral movement of tibia
3.Medial collateral ligament prevents a.Anterior movement of tibia in relation to femur b.Posterior movement of tibia in relation to femur c.Medial movement of tibia d.Lateral movement of tibia
4.Lateral collateral ligament prevents a.Anterior movement of tibia in relation to femur b.Posterior movement of tibia in relation to femur c.Medial movement of tibia d.Lateral movement of tibia
5.What are the two bundles ACL is made up of a.Anteromedial and posterolateral b.Posteromedial and anterolateral c.Mediolateral and cephalocaudal d.None of the above
The confluence of sinuses or torcular herophili is the connecting point of the superior sagittal sinus, straight sinus, and occipital sinus. It is found deep to the occipital protuberance of the skull. Blood arriving at this point then proceeds to drain into the left and right transverse sinuses.
The superior sagittal sinus often drains into (either exclusively or predominantly) one transverse sinus, and the occipital sinus drains into the other.
Confluence of sinuses
An older term often used for the confluence of sinuses "torcular herophili", describes the veins as a gutter, or canal, and honors Herophilos, the Greek anatomist who was the first to use cadavers for the systematic study of anatomy. This term more precisely refers to the concavity in the bone which is the location of the confluence of sinuses.
Anatomic area formed at lower end of thoracic esophagus by diaphragm inferiorly, pericardium anteriorly and superiorly, and descending aorta posteriorly.
For those wondering about the importance of this triangle, this traingle contains the esophagus and helps the surgeons performing various oesophageal surgical procedures like thoracoscopic oesophagomyotomy.
The surgeons approach the esophagus in the inferior mediastinum through this triangle.
An upper transverse line also known as Addison's Plane, located halfway between the jugular notch and the upper border of the pubic symphysis. It is also said to lie roughly a hand's breadth beneath the xiphoid process of the human sternum. The plane in most cases cuts through the pylorus of the stomach, the tips of the ninth costal cartilages and the lower border of the first lumbar vertebra.
The transpyloric plane is clinically notable because it passes through several important abdominal structures. These include:
lumbar vertebra 1 and hence passes just before the end of the spinal cord in adults.
the fundus of the gallbladder
the neck of the pancreas
the pancreatic body
the origin of the superior mesenteric artery from the abdominal aorta and
termination of the superior mesenteric vein at the hepatic portal vein
the left and right colic flexure
hilum of the kidney on the left
upper pole of the kidney on the right
the root of the transverse mesocolon
duodenojejunal flexure
the 1st part of the duodenum
the upper part of conus medullaris
the spleen
the pylorus of the stomach which will lie at this level approximately 5 cm to the right of the midline.
p.s: I want the readers to note that the image depicted above shows the transpyloric plane to be passing through the hilum of both kidneys, which infact is not true. The transpyloric plane actually passes through the upper pole of right kidney and the hilum of left kidney as mentioned in the description below the image. The cause of the error is probably because the artist depicted both the kidneys at equal height rather than the actual fact that the right kidney is inferior to the left kidney due to the liver above.
The scalene muscles are a group of three pairs of muscles in the lateral neck, namely the scalenus anterior, scalenus medius, and scalenus posterior.
They are innervated by the spinal nerves C4-C6.
The Scalenus anterior (Scalenus anticus), also known as anterior scalene muscle, lies deeply at the side of the neck, behind the Sternocleidomastoideus.
It arises from the anterior tubercles of the transverse processes of the third, fourth, fifth, and sixth cervical vertebræ, and descending, almost vertically, is inserted by a narrow, flat tendon into the scalene tubercle on the inner border of the first rib, and into the ridge on the upper surface of the rib in front of the subclavian groove.
It can be involved in certain forms of Thoracic outlet syndrome.
The Scalenus medius, the largest and longest of the three scalene muscles, arises from the posterior tubercles of the transverse processes of the lower six cervical vertebræ. It descendes along the side of the vertebral column to insert by a broad attachment into the upper surface of the first rib, between the tubercle and the subclavian groove. The brachial plexus and the subclavian artery pass anterior to it. Because it elevates the upper ribs, the middle scalene muscle is also one of the accessory muscles of respiration.
The
Scalenus posterior (Scalenus posticus), the smallest and most deeply seated of the three Scaleni, arises, by two or three separate tendons, from the posterior tubercles of the transverse processes of the lower two or three cervical vertebræ, and is inserted by a thin tendon into the outer surface of the second rib, behind the attachment of the Scalenus anterior.
It is occasionally blended with the Scalenus medius.
The great saphenous vein (GSV), also long saphenous vein, is the large (subcutaneous) superficial vein of the leg and thigh.
The GSV originates from where the dorsal vein of the first digit (the large toe) merges with the dorsal venous arch of the foot.
After passing anterior to the medial malleolus (where it often can be visualized and palpated), it runs up the medial side of the leg. At the knee, it runs over the posterior border of the medial epicondyle of the femur bone.
The great saphenous vein then courses medially to lie on the anterior surface of the thigh before entering an opening in the fascia lata called the saphenous opening.
It joins with the femoral vein in the region of the femoral triangle at the saphenofemoral junction.
TRIBUTARIES:
At the ankle it receives branches from the sole of the foot through the medial marginal vein; in the lower leg it anastomoses freely with the small saphenous vein, communicates with the anterior and posterior tibial veins and receives many cutaneous veins; in the thigh it communicates with the femoral vein and receives numerous tributaries; those from the medial and posterior parts of the thigh frequently unite to form a large accessory saphenous vein which joins the main vein at a variable level. Near the fossa ovalis it is joined by the superficial epigastric, superficial iliac circumflex, and superficial external pudendal veins.
The thoracoepigastric vein runs along the lateral aspect of the trunk between the superficial epigastric vein below and the lateral thoracic vein above and establishes an important communication between the femoral vein and the axillary vein .
USES IN SURGICAL PRACTICE:
The vein is often removed by vascular surgeons and used for autotransplantation in coronary artery bypass operations, when arterial grafts are not available or many grafts are required, such as in a triple bypass or quadruple bypass.
The great saphenous vein is the conduit of choice for vascular surgeons, when available, for doing peripheral arterial bypass operations because it has superior long-term patency compared to synthetic grafts (PTFE, PETE (Dacron)), human umbilical vein grafts or biosynthetic grafts [Omniflow]. Often, it is used in situ (in place), after tying off smaller tributaries and stripping the valves with a device called LeMaitre's valvulotome.
The saphenous nerve is a branch of the femoral nerve that runs with the great saphenous vein and is often damaged in surgeries that make use of the similarly named vein.
When emergency resuscitation with fluids is necessary, and standard intravenous access can not achieved due to venous collapse, saphenous vein cutdown may be necessary.
PATHOLOGIES ASSOCIATED:
Pathology of the great saphenous vein is relatively common, but in isolation typically not life threatening. Varicose veins: The great saphenous vein, like other superficial veins, can develop varices, which are generally considered to be unsightly. Various treatment options exist for treating varicose veins. Varicose veins are not life threatening. Phlebitis: The great saphenous vein can become infected. Thrombophlebitis: The great saphenous vein can thrombose and become infected. Thrombophlebitis of the great saphenous vein is not life threatening in isolation; however, it may be associated with deep vein thrombosis which can be and thus requires further investigation.
(medially) the medial border of the adductor longus muscle
(laterally) medial border of the sartorius muscle
Its floor is provided laterally by iliopsoas, medially by pectineus and adductor longus. Its roof is formed by the fascia lata.
The femoral triangle is shaped like the sail of a ship.
Its boundaries can be remembered using the mnemonic, "SAIL" for Sartorius, Adductor longus and Inguinal Ligament.
CONTENTS :
It is important as a number of vital structures pass through it, right under the skin. The following structures are contained within the femoral triangle (from lateral to medial):
terminal part of the femoral nerve and its branches
femoral sheath
femoral artery and its branches
femoral veins and its tributaries
femoral canal, containing the deep inguinal lymph nodes (snell, 8th edition)
- FLOOR
iliopsoas
pectineus
adductor longus
Lacunar Ligament
- ROOF is formed by the skin and fascia lata.
CLINICAL SIGNIFICANCE:
Since the femoral triangle provides easy access to a major artery, coronary angioplasty and peripheral angioplasty is often performed by entering the femoral artery at the femoral triangle. Heavy bleeding in the leg can be stopped by applying pressure to points in the femoral triangle. Another clinical significance of the femoral triangle is that the femoral artery is positioned at the midinguinal point (midpoint between the pubic symphysis and the anterior superior iliac spine); medial to it lies the femoral vein. Thus the femoral vein, once located, allows for femoral venopuncture[citation needed]. Femoral venopuncture is useful when there are no superficial veins that can be aspirated in a patient, in the case of collapse.
The positive pulsation of the femoral artery signifies that the heart is beating and also blood is flowing to the lower extremity[citation needed].It is also necessary to appreciate clinically that this is a case where the nerve is more lateral than the vein. In most other cases the a nerve (relative to its associated artery and vein)would be the deepest or more medial followed by the artery and then the vein. But in this case it is the opposite. This must be remembered when venous or arterial samples are required from the femoral vessels. The order of this neurovascular bundle can be remembered using the mnemonic, "NAVY" for Nerve, Artery, Vein, Y -fronts (the British term of a style of men's underwear with a "Y" shaped front that acts as a fly). The "Y" is midline (corresponding with the penis) and the mnemonic always reads from the outside - in, so that the Femoral Nerve is always lateral. An alternate to this mnemonic is "NAVaL" for Nerve, Artery, Vein, and Lymph, to include the deep inguinal lymph nodes located medial to the Femoral vein.
The inion is the most prominent projection of the occipital bone at the posterioinferior (lower rear) part of the skull. The ligamentum nuchae and trapezius muscle attach to it.
The term external occipital protuberance (protuberantia occipitalis externa) is sometimes used as a synonym, but more precisely the term "inion" refers to the highest point of the external occipital protuberance.
The word "inion" is the Greek word for the occipital bone.
An Anatolian bump is a protuberance on the back of the skull said to be related to East and Central Asian ancestry, especially Turkic tribes.It is an unusually large external occipital protuberance.
The third ventricle (ventriculus tertius) is one of four connected fluid-filled cavities comprising the ventricular system within the human brain. It is a median cleft between the two thalami, and is filled with cerebrospinal fluid (CSF).
It is in the midline, between the left and right lateral ventricles.
It communicates with the lateral ventricles anteriorly by the interventricular foramina (of Monro).
It communicates with the fourth ventricle posteriorly by the cerebral aqueduct (of Sylvius).
The third ventricle, similarly to other parts of the ventricular system of the brain, develop from the central canal of the neural tube. Specifically, the third ventricle originates from the portion of the tube that is present in the developing prosencephalon, and subsequently in the developing encephalopathy.
It is bounded by the thalamus and hypothalamus on both the left and right sides. The lamina terminalis forms the anterior wall of the third ventricle.
There are two protrusions on the front of the third ventricle:
the supra-optic recess (above the optic chiasma)
the infundibular recess (above the pituitary stalk).
In casts of the ventricular system, a small 'hole' may be seen in the body of the third ventricle. This is formed where the two thalami are joined together at the interthalamic adhesion (not seen in all people).
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Now that u have finished reading go here and try answering a question. Read and try answering question 103 in that paper given in the link. Answers are given below the presentation.
The interpeduncular cistern (basal cistern or Fossa interpeduncularis) is a wide cavity where the arachnoid extends across between the two temporal lobes.
It encloses the cerebral peduncles and the structures contained in the interpeduncular fossa, and contains the arterial circle of Willis.
Diagram showing the positions of the three principal subarachnoid cisternæ. Interpeduncular cistern labeled at left center.
1. Middle superior alveolar nerve is a branch of
a) Mandibular division of trigeminal nerve
b) Palatine division of maxillary nerve
c) Anterior nasal division of maxillary nerve
d) Inferior alveolar nerve
2. All the following muscles retracts the scapula EXCEPT
a) Trapezius
b) Rhomboid major
c) Rhomboid minor
d) Levator scapulae
3. Cranial nerve NOT carrying parasympathetic fibres
a) 4th
b) 7th
c) 3rd
d) 9th
4. Prostatic urethra – True are A/E
a) Trapezoid in cross section
b) Elevated round swelling called verumontanum
c) Opening of prostatic ducts
d) Posterior part has urethral crest
5. Morgagni hernia presents most commonly on
a) Left posterior
b) Right anterior
c) Right posterior
d) Left anterior
6. Meralgia parasthetica is due to involvement of
a) Sural nerve
b) Medial cutaneous nerve of thigh
c) Lateral cutaneous nerve of thigh
d) Peroneal nerve
7. Celiac plexus is located
a) Anterolateral & around the aorta
b) Posterolateral & around the aorta
c) Anteromedial to lumbar sympathetic chain
d) Posterolateral to lumbar sympathetic chain
8. Paneth cells – True is
a) Rich in rough endoplasmic reticulum
b) High zinc content
c) Foamy cytoplasm
d) Numerous lysozyme granules
9. About sternocleidomastoid tumor all are true except –
a) Always associated with breech
b) Spontaenous resolution in most cases
c) Two-third have palpable neck mass at birth
d) Uncorrected cases develops plagiocephaly
10. The function of 8th cranial nerve is related to
a) Smell
b) Taste
c) Touch
d) Balance
11. Anterior ethmoidal nerve supplies all except?
a. Maxillary sinus
a) Interior of nasal cavity
b) Dural sheath of anterior cranial fossa
c) Ethmoidal air cells
12. A healthy young athlete is sitting at the edge of the table with knee at 90 degree
flexion. He fully extends it. What will happen?
a) Movement of tibial tuberosity towards lateral border of patella
b) Movement of tibial tuberosity towards medial border of patella
c) Movement of tibial tuberosity towards centre of patella
d) No change in position
13. Pain insensitive structure in brain is
a) Falx cerebri
b) Dural sheath surrounding vascular sinuses
c) Choroid plexus
d) Middle meningeal artery
14. Appendices epiploiceae present in
a) Appendix
b) Cecum
c) Rectum
d) Sigmoid colon
15. Pelvic splanchnic nerve supplies A/E
a) Appendix
b) Rectum
c) Uterus
d) Urinary bladder
A. Pain Insensitive structures in Brain : (Intracranial)
1. Brain parenchyma
2. Ependyma
3. Choroid plexus
4. Piamatter
5. Arachnoid
6. Dura over convexity of skull ( Dura around vascular sinuses and vessels is sensitive to pain)
B. Pain Sensitive structures in Brain : B1. Intracranial :
1. Cranial venous sinuses with afferent veins
2. Arteries at base of brain and arteries of dura including middle meningeal artery
3. Dura around venous sinuses and vessels
4. Falx cerebri
The peroneus brevis muscle (or fibularis brevis) lies under cover of the peroneus longus, and is a shorter and smaller muscle.
It arises from the lower two-thirds of the lateral surface of the body of the fibula; medial to the Peroneus longus; and from the intermuscular septa separating it from the adjacent muscles on the front and back of the leg.
The fibers pass vertically downward, and end in a tendon which runs behind the lateral malleolus along with but in front of that of the preceding muscle, the two tendons being enclosed in the same compartment, and lubricated by a common mucous sheath.
It then runs forward on the lateral side of the calcaneus, above the trochlear process and the tendon of the Peronæus longus, and is inserted into the tuberosity at the base of the fifth metatarsal bone, on its lateral side.
The terms "Peroneal" (i.e., Artery, Retinaculum) and "Peroneus" (i.e., Longus and Brevis) are derived from the Greek word Perone (pronounced Pair-uh-knee) meaning pin of a brooch or a buckle. In medical terminology, both terms refer to being of or relating to the fibula or to the outer portion of the leg.
