The antebrachial fascia (antibrachial fascia or deep fascia of forearm) continuous above with the brachial fascia, is a dense, membranous investment, which forms a general sheath for the muscles in this region; it is attached, behind, to the

olecranon The olecranon (, ), is a large, thick, curved bony eminence of the ulna, a long bone in the forearm that projects behind the elbow. It forms the most pointed portion of the elbow and is opposite to the cubital fossa or elbow pit. The olecranon ...

and dorsal border of the

ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...

, and gives off from its deep surface numerous intermuscular septa, which enclose each muscle separately. Over the

flexor muscles Anatomical terminology is a form of scientific terminology used by anatomists, zoologists, and health professionals such as doctors. Anatomical terminology uses many unique terms, suffixes, and prefixes deriving from Ancient Greek and Latin. ...

tendon A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability ...

s as they approach the wrist it is especially thickened, and forms the volar carpal ligament. This is continuous with the

transverse carpal ligament The flexor retinaculum (transverse carpal ligament, or anterior annular ligament) is a fibrous band on the palmar side of the hand near the wrist. It arches over the carpal bones of the hands, covering them and forming the carpal tunnel. Structur ...

, and forms a sheath for the tendon of the

palmaris longus The palmaris longus is a muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much long ...

which passes over the

to be inserted into the

palmar aponeurosis The palmar aponeurosis (palmar fascia) invests the muscles of the palm, and consists of central, lateral, and medial portions. Structure The central portion occupies the middle of the palm, is triangular in shape, and of great strength Its apex ...

. Behind, near the wrist-joint, it is thickened by the addition of many transverse fibers, and forms the

dorsal carpal ligament The extensor retinaculum (dorsal carpal ligament, or posterior annular ligament) is an anatomical term for the thickened part of the antebrachial fascia that holds the tendons of the extensor muscles in place. It is located on the back of the fore ...

. It is much thicker on the dorsal than on the volar surface, and at the lower than at the upper part of the forearm, and is strengthened above by tendinous fibers derived from the Biceps brachii in front, and from the

Triceps brachii The triceps, or triceps brachii (Latin for "three-headed muscle of the arm"), is a large muscle on the back of the upper limb of many vertebrates. It consists of 3 parts: the medial, lateral, and long head. It is the muscle principally respon ...

behind. It gives origin to muscular fibers, especially at the upper part of the medial and lateral sides of the forearm, and forms the boundaries of a series of cone-shaped cavities, in which the muscles are contained. Besides the vertical septa separating the individual muscles, transverse septa are given off both on the volar and dorsal surfaces of the forearm, separating the deep from the superficial layers of muscles. Apertures exist in the fascia for the passage of vessels and nerves; one of these apertures of large size, situated at the front of the

elbow The elbow is the region between the arm and the forearm that surrounds the elbow joint. The elbow includes prominent landmarks such as the olecranon, the cubital fossa (also called the chelidon, or the elbow pit), and the lateral and the me ...

, serves for the passage of a communicating branch between the superficial and deep veins.

References

Forearm Fascia {{muscle-stub