The brachial Fascia is continuous with that covering the Deltoideus and the Pectoralis major, by means of which it is attached, above, to the clavicle

Clavicle

In human anatomy, the clavicle or collar bone is a long bone of short length that serves as a strut between the scapula and the sternum. It is the only long bone in body that lies horizontally...

, acromion, and spine of the scapula; it forms a thin, loose, membranous sheath for the muscles of the arm, and sends septa between them; it is composed of fibers disposed in a circular or spiral direction, and connected together by vertical and oblique fibers.

It differs in thickness at different parts, being thin over the Biceps brachii, but thicker where it covers the Triceps brachii, and over the epicondyles of the humerus

Humerus

The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....

: it is strengthened by fibrous aponeuroses, derived from the Pectoralis major and Latissimus dorsi medially, and from the Deltoideus laterally.

On either side it gives off a strong intermuscular septum

Intermuscular septum

Intermuscular septum can refer to:* medial intermuscular septum of arm* medial intermuscular septum of thigh* lateral intermuscular septum of arm* lateral intermuscular septum of thigh...

, which is attached to the corresponding supracondylar ridge

Supracondylar ridge

Supracondylar ridge can refer to:* Lateral supracondylar ridge* Medial supracondylar ridge...

 and epicondyle

Epicondyle

Epicondyle may refer to:...

of the humerus.