Gluteal region,

posterior compartment of the thigh

Class: JC1 2012/2013Course: Neuromuscular moduleCode: NM7Lecturer: Ahmed M. Saliem.Date: 1st/ October/ 2012.

ahmed@pu-rcsi.edu.my

Learning objectives• Describe the bony pelvis, including parts, joints and ligaments• Describe the femur, including articular surfaces, attachments and bony features• Define the boundaries of the gluteal region• Describe the superficial gluteal muscles, and describe their attachments, innervations and actions• Explain how trendelenburg gait occurs• Name the deep muscles of the gluteal region, including attachments and actions• Describe the sciatic nerve, including origin, root values and its two parts• Identify the boundaries of the greater sciatic foramen• Describe the structures passing through the greater sciatic foramen and their relative positions• Identify the boundaries of the lesser sciatic foramen• Name the structures passing through the lesser sciatic foramen • Explain the anatomy of intramuscular injections to the gluteal region• Describe the posterior compartment of the thigh• Name the muscles of the posterior compartment of the thigh, and describe their attachments,

innervations and actions• Describe the sciatic nerve in the thigh, including course and main branches• Explain the vascular supply to the posterior compartment of the thigh. Ischial spine, ischial

tuberosity, greater trochanter • Semimembranosus, semitendinosus & biceps femoris (Hamstring muscles)

Proximal Femur• Greater and lesser

trochanters – attachment sites for the muscles which move the hip joint

Femoral head

Gluteal Muscles• Abduct, extend and laterally rotate the hip

joint

• Deep muscles:– Piriformis– Obturator internus– Gemellus superior– Gemellus inferior– Quadratus femoris

• Superficial muscles:– Gluteus minimus– Gluteus medius– Gluteus maximus– Tensor fascia lata

Gluteal Muscles-Deep

Gluteal Muscles-Deep• Piriformis

– Origin: anterior sacrum– Insertion: passes through

GSF, inserts on greater trochanter of femur

– Action: laterally rotates hip– Nerve Supply: branches from

L5, S1, S2

• Obturator Internus– Origin: deep surface of

obturator membrane and surrounding bone

– Insertion: medial greater trochanter

– Action: laterally rotates hip– Nerve Supply: nerve to

obturator iternus (L5, S1)

• Gemellus superior and inferior– Origin: ischial spine and

tuberosity– Insertion: greater trochanter– Action: laterally rotate hip– Nerve supply:

Sup – nerve to obtuator internusInf – nerve to quadratus femoris

• Quadratus femoris– Origin: lateral ischium– Insertion: intertrochanteric

crest of femur– Action: laterally rotates hip– Nerve supply: nerve to

Quadratus femoris (L5, S1)

Gluteal Muscles-Superficial• Gluteus maximus:• Largest gluteal muscle and

overlies all other gluteal muscles– Origin: external surface of

ilium, lower sacrum, lateral coccyx,

– Insertion: posterior aspect of the iliotibial tract and gluteal tuberosity of proximal femur

– Action: powerful extensor of the hip

– Nerve supply: inferior gluteal nerve (L5, S1, S2)

Gluteal Muscles-Superficial• Gluteus medius:

– Origin: external surface of ilium, overlying gluteus minimus

– Insertion: fibers converge to a tendon which inserts on lateral greater trochanter

– Action: abduct the hip and reduce pelvic drop during gait

– Nerve supply: superior gluteal nerve (L4, L5, S1)

Gluteal Muscles-Superficial• Gluteus minimus:

– Origin: external surface of ilium

– Insertion: fibers converge to a tendon which inserts on anterolateral greater trochanter

– Action: abduct the hip and reduce pelvic drop during gait

– Nerve supply: superior gluteal nerve (L4, L5, S1)

Gluteal Muscles-Superficial• Tensor Fascia Lata

– Origin: outer margin of iliac crest

– Insertion: anterior aspect of iliotibial tract, which runs down the lateral thigh to attach to the upper tibia

– Action: stabilises the knee in extension

– Nerve supply: superior gluteal nerve

(L4, L5, S1)

Trendelenburg Gait

Gluteus Medius Muscle weakness on the Right side, with contralateral drop of the pelvis

Posterior Compartment of the thigh• Hamstrings muscles

– All cross both the hip and knee joint except the short head of biceps femoris

– As a group the Hamstrings flex the leg at the knee joint, extend the thigh at the hip joint. They are also rotators at both joints.

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Posterior Compartment of the thigh• Biceps Femoris

– Origin: long head – ischial tuberosityshort head – lateral lip of the linea aspera on the shaft

of the femur– Insertion: two heads join to form a tendon to insert into the lateral

surface of the head of the fibula– Action: flexes the leg at the knee joint. Long head extends and laterally

rotates the hip. When the knee is flexed, it can laterally rotate the leg at the knee joint

– Innervation:long head – tibial division of Sciatic Nerve (L5,S1,S2)short head – common fibular division of the SciaticNerve (L5,S1,S2)

Posterior Compartment of the thigh• Semitendinosus

– Origin: ischial tuberosity– Insertion: medial surface of

the proximal tibia.– Action: flexes the leg at the

knee joint, extends thigh, when the knee is flexed it medially rotates the leg at the knee joint

– Innervation: tibial division of the Sciatic Nerve L5,S1,S2

Posterior Compartment of the thigh• Semimebranosus

– Origin: ischial tuberosity– Insertion: medial and posterior

surfaces of the medial tibial condyle. Expansions of the tendon also insert into the ligament and fascia around the knee joint.

– Action: flexes the leg at the knee joint, extends the thigh, when knee is flexed it medially rotates the leg at the knee joint

– Innervation: tibial division of the sciatic nerve L5,S1,S2.

Hamstring injuries• Common in running

and kicking activities.

• Strong muscular exertions can result in a tear at either the ischial tuberosity or in the muscle belly.

Greater and Lesser Sciatic foramina

Lesser Sciatic Foramen

Greater Sciatic Foramen

Greater and Lesser Sciatic foramina• Greater Sciatic Foramen

– Major route for structures to pass between the pelvis and the gluteal region of the lower limb.

– Piriformis muscle passes out from the pelvis to the gluteal region through the sciatic foramen which separates it into two parts, a part above the muscle and a part below the muscle.

Greater and Lesser Sciatic foramina

• Above the piriformis:– Superior gluteal nerve and vessels

• Below the piriformis:– Sciatic nerve– Inferior gluteal nerves and vessels– Pudendal nerve and internal pudendal vessles– Posterior cutaneous nerve of thigh– Nerve to obturator internus and gemellus superior– Nerve to quadratus femoris and gemellus inferior.

Greater and Lesser Sciatic foramina

• Lesser Sciatic Foramen–Connects the gluteal region with the

perineum–Structures passing through:

• Tendon of obturator internus• Pudendal nerve and internal pudendal vessels

(exit the pelvis through the GSF, enter the perineum through the LSF)

Sciatic nerve• Largest nerve in the body• Nerve root: L4 to S3• Leaves the pelvis through the

greater sciatic foramen inferior to piriformis

• Enters and passes through the gluteal region

• Enters the posterior compartment of the thigh• Supplies:

– all the muscles of the posterior compartment of the thigh, – part of the adductor magnus muscle, – all muscles of the leg and foot, – skin on the lateral side of the leg and lateral side of the sole

of the foot

Scia

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Sciatic nerve-Sciatica• Sciatica is pain in the leg

as a result of irritation of the sciatic nerve

• Pain follows the course if the nerve, from the buttocks, down the back of the thigh and calf

• Caused generally by compression of a lumbar spine nerve root, and far less commonly by compression of the sciatic nerve itself

Gluteal Nerve• Superior Gluteal nerve

– Passes through the GSF above piriformis

– Travels superiorly and laterally between gluteus minimus and medius

– Supplies Gluteus minimus, Gluteus medius, tensor fascia lata

Gluteal/Pudendal Nerve• Inferior Gluteal nerve

– Passes through the GSF below piriformis

– Penetrates and supplies gluteus maximus

• Pudendal nerve– Passes through GSF

below piriformis– Passes over

sacrospinous ligament and into LSF to enter perineum

Gluteal Arteries

• Inferior Gluteal Artery– Originates from the internal iliac

artery– Enters the gluteal region with

the inferior gluteal nerve (GSF below piriformis)

– Supplies adjacent muscles

• Superior Gluteal Artery– Originates from the internal

iliac artery– Enters the gluteal region with

the superior gluteal nerve (GSF above piriformis)

– Divides into superficial and deep branches

– Supplies adjacent muscles, and contributes to the blood supply of the hip

References • Clinically oriented anatomy by regions 8th

edition: Richard S. Snell.• Essential clinical anatomy 4th edition: Keith

L. Moore.• Clinically Oriented Anatomy 6th edition:

Keith L. Moore.• Clinical anatomy 2nd edition: Stanley

Monkhouse.

The EndThank you