Hip Muscles – Gluts and Piriformis

 Hip Muscles: The Gluts and Piriformis Muscles

(modified from teach me anatomy site 2018)

The gluteal region is at the back of your pelvis, at the top end of the femur. TThis allows the muscles to move the lower limb at the hip joint and to provide stabilisation when you stand on one leg.

The muscles consist of two groups:

  • Superficial sideways and backwards movers are  large muscles that abduct and extend the femur: gluteus maximus, gluteus medius, gluteus minimus and tensor fascia lata.
  • Deep turn out muscles are smaller muscles that mainly act to laterally rotate the femur. Includes the quadratus femoris, piriformis, ( small gemellus superior and inferior and obturator internus).

The Superficial Muscles  abduct and extend the lower limb at the hip joint.

Gluteus Maximus

Fig 1.0 - The superficial muscles of the gluteal region. The gluteus maximus and medius have been partly removed.

Fig 1 – The superficial muscles of the gluteal region. The gluteus maximus and medius have been partly removed.

The gluteus maximus is the largest of the gluteal muscles. It is also the most superficial, producing the shape of the buttocks. (green muscle cut and folder back in picture).

  • Attachments: it originates from the gluteal (back) surface of the ilium, sacrum and coccyx. It slopes across the buttock at a 45-degree angle, inserts into the iliotibial tract and the gluteal tuberosity of the femur.
  • Actions: It is the main extensor of the thigh, and assists with lateral rotation. However, it is only used when force is required, such as running or climbing.
  • Innervation: Inferior gluteal nerve.

Gluteus Medius

The gluteus medius muscle is fan-shaped and lies between to the gluteus maximus and the minimus.

  • Attachments: Originates from the gluteal surface of the ilium and inserts into the lateral surface of the greater trochanter (on the top of the femur).
  • Actions: Abducts and medially (internally) rotates the lower limb. During walking, it secures the pelvis, preventing a drop of the pelvis of the opposite limb.
  • Innervation: Superior gluteal nerve.

Gluteus Minimus

The gluteus minimus is the deepest and smallest buttock muscle.

  • Attachments: Originates from the ilium and converges to form a tendon, inserting to the anterior side of the greater trochanter.
  • Actions: Abducts and medially rotates the lower limb. During walking it secures the pelvis, preventing a pelvic drop of the opposite limb.
  • Innervation: Superior gluteal nerve.

Tensor Fascia Lata (TFL)

Tensor fasciae lata is a small superficial muscle which lies towards the anterior edge of the iliac crest. It  tightens the fascia lata, and so abducts and medially rotates the lower limb.

  • Attachments: Originates from the anterior iliac crest, the front bones of your pelvis (ASIS). It inserts into the iliotibial tract on the femur, then to the lateral condyle of the tibia.
  • Actions: Assists the gluteus medius and minimus in abduction and medial rotation of the lower limb. It also plays a supportive role in the gait cycle.
  • Innervation: Superior gluteal nerve.

Clinical Relevance: Weakness of Gluteus Medius do to Postural Habits, Pain or Damage to the Superior Gluteal Nerve

Fig 1.1 - Positive Trendelenburg test, a sign of left superior gluteal nerve palsy.

Fig 2 – Positive Trendelenburg sign, characteristic of left superior gluteal nerve palsy.

In the standing position, the gluteus minimus and medius contract when the contralateral leg is raised, preventing the pelvis from dropping on that side. If the superior gluteal nerve is damaged, the muscles are paralysed – and the pelvis becomes unsteady.

Trendelenburg sign.

A characteristic finding of gluteal muscle weakness is the Trendelenburg sign. It is produced when your pelvis drops when you stand on one leg.

EG: if the left gluteal muscles are weak, the right side of the pelvis will drop when you stand on your left leg (and the right leg is unsupported).

The Deep Muscles

The deep gluteal muscles are smaller muscles, underneath the gluteus minimus. The general action of these muscles is to laterally rotate (they turn the kneecap outward and raise the arch of your foot) . They also stabilise the hip joint by ‘pulling’ the femoral head into the acetabulum of the pelvis.

Piriformis

The piriformis muscle is the most superior of the deep muscles. It often feels very tight and painful to touch. It can be tight due to pain anywhere in the low lumbar spine, sacroiliac joint or hip.

  • Attachments: Originates from the anterior surface of the sacrum. It then travels infero-laterally, through the greater sciatic foramen, to insert into the greater trochanter of the femur.
  • Actions: Lateral rotation and abduction.
  • Innervation: Nerve to piriformis.

Obturator Internus

Fig 1.2 - The deep muscles of the gluteal region.

Fig 3 – The deep muscles of the gluteal region.

The obturator internus forms the lateral walls of the pelvis

  • Attachments: Originates from the pubis and ischium at the obturator foramen then travels through the lesser sciatic foramen and attaches to the greater trochanter of the femur.
  • Actions: Lateral rotation and abduction.
  • Innervation: Nerve to obturator internus.

The Gemelli – Superior and Inferior Muscles

The gemelli are two narrow and triangular muscles. They are separated by the obturator internus tendon.

  • Attachments: The superior gemellus muscle originates from the ischial spine, the inferior from the ischial tuberosity. They both attach to the greater trochanter of the femur.
  • Actions: Lateral rotation and abduction.
  • Innervation: The superior gemellus muscle (nerve to obturator internus), the inferior gemellus (nerve to quadratus femoris).

Quadratus Femoris

The quadratus femoris is a flat, square-shaped muscle. It is the most inferior of the deep gluteal muscles.

  • Attachments: It originates from the lateral side of the ischial tuberosity, and attaches to the quadrate tuberosity on the intertrochanteric crest.
  • Actions: Lateral rotation.
  • Innervation: Nerve to quadratus femoris.

Clinical Relevance: Piriformis

As the piriformis muscle travels through the greater sciatic foramen, it divides the gluteal region into an inferior and superior part.  The sciatic nerve (a major peripheral nerve of the lower limb). The sciatic nerve enters the gluteal region directly inferior to the piriformis and feels like a flat band, approximately 2cm wide

Fig 1.3 - The piriformis as an anatomical landmark in the gluteal region.

Fig 4 – The piriformis (green)

Piriformis often responds to treatment by heat, massage and stretching. However it is most important to discover the reason for piriformis being tight. Is there a back, pelvis or hip joint pain causing the muscle to react?

Please Call 93816166 or Email helen@intouchphysio.com.au

for further information on how I can help

Helen Potter Specialist Physiotherapist Subiaco

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