[PT Y1 A2] Posterior Compartment

Semitendinosus ("half tendon", referring to its long tendon of insertion) OINA

Origin: Ischial tuberosity by tendon shared with long head of biceps femoris Insertion: Upper part of medial surface of tibia behind sartorius and gracilis Deep fascia of leg Action: Flexes and medially rotates knee Extends and medially rotates hip Nerve: Tibial PORTION of sciatic n. (L5, S1, 2)

Note: ___ ___ ___ are known as the tripod muscles because their distal attachments converge to an apex of three combined tendons of insertion known as the ____ ("goose's foot").

Sartorius, gracilis and semitendinosus pes anserinus

E. Posterior muscles of the thigh 1) General features a) The muscles of the back of the thigh or _____ are the biceps femoris (lateral hamstring), s______ (medial hamstrings). b) Except for the short head of the biceps, these muscles arise from the ischial tuberosity, cross both the hip and knee joints, and are innervated by the tibial portion of the sciatic nerve. Their primary actions are to flex the leg and to extend the thigh. c) All of these muscles receive their blood supply from the _____, a branch of the femoral artery.

hamstrings semitendinosus and semimembranosus profunda femoris artery

B. Obturator artery 1) The is a branch of the ____ in the pelvis. It enters the thigh with the obturator nerve by passing through the obturator canal. 2) Branches of the obturator artery supply the ____ near the obturator membrane and the hip joint (acetabulum and head of femur).

internal iliac artery adductor muscles

IV. Nerves A. Femoral nerve ____ 1) The femoral nerve, the largest branch of the lumbar plexus, arises from the posterior divisions of the ____ of L2, 3,4. 2) It descends through the fibers of ____, emerging from the muscle at the lower part of its lateral border, and passes down between it and iliacus. It then passes behind the inguinal ligament to enter the thigh where it breaks up into a number of terminal branches. 3)_____ supply ____ ____ ___ ___ ___ 4) Cutaneous branches a) The intermediate and medial cutaneous nerves of the thigh supply the ____. b) The ____ is the largest cutaneous branch of the femoral nerve. It descends with the femoral vessels in the adductor canal and becomes cutaneous just above the knee. It supplies the skin on the ____

(L2, 3, 4) ventral rami psoas major Muscular branches iliacus, sartorius, quadriceps femoris and pectineus. skin on the front and medial side of the thigh saphenous nerve medial side of the leg and foot.

3) Branches of the sciatic nerve in the thigh a) The tibial nerve innervates the long head of ____ ____ ___ -__ b) The common fibular (peroneal) nerve supplies the ____

biceps femoris, semitendinosus, semimembranosus, and the ischiocondylar portion of adductor magnus short head of biceps femoris. .

B. Obturator nerve (____) 1) The obturator nerve, and accessory obturator (L3, 4) when present (8-10% of subjects), are the anterior division nerves of the lumbar plexus. 2) The obturator nerve descends through the fibers of ___and emerges from its medial border at the pelvic brim. It then accompanies the obturator vessels to the obturator canal, through which it enters the thigh. Near the canal, it divides into an ____ ____, which are separated by the adductor brevis. a) The anterior branch supplies a small area of skin on the medial side of the thigh and innervates ____ ___ ___ ___ b) The posterior branch supplies ___ and ____

L2, 3, 4 psoas major anterior and a posterior branch gracilis, adductor longus, adductor brevis, and sometimes pectineus. adductor magnus and obturator externus.

III. Arteries A. Femoral artery 1) The femoral artery is the continuation of the ____ below the level of the inguinal ligament. It spirals medially down the front and medial side of the thigh. a) In the upper third of the thigh it lies superficially in the f____ . b) In the middle third it lies in the adductor canal deep to sartorius. c) In the lower third it passes through an opening in the adductor magnus (ADDUCTOR HIATUS) and changes its name to ____.

external iliac femoral triangle popliteal artery

____ nerve is ____ comming off of tibial and fibular nerve

sural, cutaneous

C. Sciatic nerve 1) The sciatic nerve is a branch of the sacral plexus. It is the largest nerve in the body, but actually consists of two nerves, the ____, that are bound together. a) Anterior divisions of the _____ unite to form the tibial nerve. b) Posterior divisions of the _____ unite to form the common fibular (peroneal) nerve. 2) The sciatic nerve leaves the pelvis and enters the gluteal region by passing through the _____, below the piriformis. It descends deep to the gluteus maximus, between the greater trochanter and ischial tuberosity, and enters the thigh. In the back of the thigh it lies on the adductor magnus and is crossed posteriorly by the long head of the biceps femoris. In the lower third of the thigh it divides into two large branches, ______ ____

tibial and common fibular (peroneal) ventral rami of L4, 5, S1 2, 3 ventral rami of L4, 5, S1, 2 greater sciatic foramen the tibial and common fibular (peroneal) nerves.

Biceps femoris arises by two heads: OINA

Origin: Long head (1) from ischial tuberosity and sacrotuberous ligament Short head from lateral lip of linea aspera, lateral supracondylar line and lateral intermuscular septum Insertion: Head of fibula, lateral condyle of tibia and deep fascia on lateral side of leg Action: Both heads flex and laterally rotate knee Long head extends and laterally rotates hip Nerve: Long head, tibial portion of sciatic n. (L5, S1, 2) Short head, common fibular (peroneal) portion of sciatic n. (L5, S1, 2)

Semimembranosus OINA Half membrane, flattened tendon of origin

Semimembranosus ("half membrane", referring to its flattened tendon of origin) (2) Origin: Ischial tuberosity Insertion: Posteromedial surface of medial condyle of tibia Action: Flexes and medially rotates knee Extends and medially rotates hip Nerve: Tibial portion of sciatic n. (L5, S1, 2)

2) Branches of the femoral artery supply the muscles of the thigh. a) Four small branches to the lower part of the abdomen: ___ ___ ___ ___ b) _____ arises in the femoral triangle and is the largest branch of the femoral artery. It runs behind the femoral artery and then descends on the medial side of the femur, lying on the adductor brevis and adductor magnus. Its perforating branches supply the hamstring muscles. In about half of cases the femoral circumflex arteries arise from the profunda femoris near its origin. (i) ____ supplies the anterior muscles of the thigh (ii) ____ supplies the adductor muscles and the most of the blood to the hip joint (head and neck of femur and acetabulum). c) The _____ near the end of the femoral artery. It anastomoses at the medial side of the knee with genicular branches of the popliteal artery.

superficial epigastric, superficial circumflex iliac, superficial external pudendal and deep external pudendal arteries. Profunda femoris (deep femoral) Lateral femoral circumflex Medial femoral circumflex descending genicular (KNEE) arises