| Piriformis nerve | |
|---|---|
 Diagram of sacral plexus and pudendal plexus. (Label "to piriformis" is at center left.) | |
 The piriformis and nearby muscles | |
| Details | |
| From | sacral plexus (S1–S2) |
| Innervates | piriformis muscle |
| Identifiers | |
| Latin | nervus musculi piriformis |
| TA98 | A14.2.07.029 |
| TA2 | 6545 |
| FMA | 16509 |
| Anatomical terms of neuroanatomy | |
The piriformis nerve, also known as the nerve to piriformis, is the peripheral nerve that provides motor innervation to the piriformis muscle.
The nerve to piriformis is a branch of the sacral plexus. [1] [2] It (typically [3] ) arises from the posterior divisions [4] /branches [3] of anterior rami of S1 and S2. [1] [2] [3] [5]
It enters the anterior surface of the piriformis muscle. [3] [6]
Origin
It may sometimes arise from the anterior ramus of S2 only. [3]
Number
It may be doubled. An additional branch may arise from the superior gluteal nerve. [3]
The piriformis nerve innervates the piriformis muscle. [1]
The axillary nerve or the circumflex nerve is a nerve of the human body, that originates from the brachial plexus at the level of the axilla (armpit) and carries nerve fibers from C5 and C6. The axillary nerve travels through the quadrangular space with the posterior circumflex humeral artery and vein to innervate the deltoid and teres minor.
The dorsal scapular nerve is a branch of the brachial plexus, usually derived from the ventral ramus of cervical nerve C5. It provides motor innervation to the rhomboid major muscle, rhomboid minor muscle, and levator scapulae muscle.
The long thoracic nerve is a branch of the brachial plexus derived from cervical nerves C5-C7 that innervates the serratus anterior muscle.
The infrahyoid muscles, or strap muscles, are a group of four pairs of muscles in the anterior (frontal) part of the neck. The four infrahyoid muscles are the sternohyoid, sternothyroid, thyrohyoid and omohyoid muscles.
The cervical plexus is a nerve plexus of the anterior rami of the first four cervical spinal nerves C1-C4. The cervical plexus provides motor innervation to some muscles of the neck, and the diaphragm; it provides sensory innervation to parts of the head, neck, and chest.
The epineurium is the outermost layer of dense irregular connective tissue surrounding a peripheral nerve. It usually surrounds multiple nerve fascicles as well as blood vessels which supply the nerve. Smaller branches of these blood vessels penetrate into the perineurium. In addition to blood vessels which supply the nerve, lymphocytes and fibroblasts are also present and contribute to the production of collagen fibers that form the backbone of the epineurium. In addition to providing structural support, lymphocytes and fibroblasts also play a vital role in maintenance and repair of the surrounding tissues.
In human anatomy, the fibularis brevis is a muscle that lies underneath the fibularis longus within the lateral compartment of the leg. It acts to tilt the sole of the foot away from the midline of the body (eversion) and to extend the foot downward away from the body at the ankle.
The medial pectoral nerve is (typically) a branch of the medial cord of the brachial plexus and is derived from spinal nerve roots C8-T1. It provides motor innervation to the pectoralis minor muscle, and the lower half of the pectoralis major muscle. It runs along the inferior border of the pectoralis minor muscle.
The thoracodorsal nerve is a nerve present in humans and other animals, also known as the middle subscapular nerve or the long subscapular nerve. It supplies the latissimus dorsi muscle.
The anterior superior iliac spine (ASIS) is a bony projection of the iliac bone, and an important landmark of surface anatomy. It refers to the anterior extremity of the iliac crest of the pelvis. It provides attachment for the inguinal ligament, and the sartorius muscle. The tensor fasciae latae muscle attaches to the lateral aspect of the superior anterior iliac spine, and also about 5 cm away at the iliac tubercle.
The posterior cutaneous nerve of the thigh is a sensory nerve of the thigh. It is a branch of the sacral plexus. It supplies the skin of the posterior surface of the thigh, leg, buttock, and also the perineum.
The superior gluteal nerve is a mixed nerve of the sacral plexus that originates in the pelvis. It provides motor innervation to the gluteus medius, gluteus minimus, tensor fasciae latae, and piriformis muscles; it also has a cutaneous branch.
The iliohypogastric nerve is a nerve that originates from the lumbar plexus that supplies sensation to skin over the lateral gluteal and hypogastric regions and motor to the internal oblique muscles and transverse abdominal muscles.
The anococcygeal nerve is a sensory nerve of the pelvis that arises from the coccygeal plexus. It pierces the coccygeus muscle and the sacrotuberous ligament to supply a small area of skin between the coccyx and anus, as well as the sacrococcygeal joint. The number of anococcygeal nerves varies between one and three.
The perforating cutaneous nerve is a cutaneous nerve of the sacral plexus that provides sensory innervation to the skin of the buttocks.
The bicipital aponeurosis is a broad aponeurosis of the biceps brachii, which is located in the cubital fossa of the elbow. It separates superficial from deep structures in much of the fossa.
The nerve to obturator internus is a mixed nerve providing motor innervation to the obturator internus muscle and gemellus superior muscle, and sensory innervation to the hip joint. It is a branch of the sacral plexus. It is one of the group of deep gluteal nerves.
The nerve to quadratus femoris is a nerve of the sacral plexus that provides motor innervation to the quadratus femoris muscle and gemellus inferior muscle, and an articular branch to the hip joint. The nerve leaves the pelvis through the greater sciatic foramen.
Pelvic splanchnic nerves or nervi erigentes are splanchnic nerves that arise from sacral spinal nerves S2, S3, S4 to provide parasympathetic innervation to the organs of the pelvic cavity.
The lumbosacral trunk is nervous tissue that connects the lumbar plexus with the sacral plexus. It is formed by the union of parts of the fourth and fifth lumbar nerves and descends to join the sacral plexus.
This article incorporates text in the public domain from page 957 of the 20th edition of Gray's Anatomy (1918)
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