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 behind.
32.
The biceps brachii, brachialis, and brachioradialis ( which attaches distally ) act to flex the elbow . ( The biceps do not attach to the humerus . ) The triceps brachii and anconeus extend the elbow, and attach to the posterior side of the humerus.
33.
Latin names of structures such as musculus biceps brachii can be split up and refer to, " musculus " for muscle, " biceps " for " two-headed ", " brachii " as in the brachial region of the arm.
34.
Probes and the prosector's own fingers are examples of tools used for blunt dissection where tissue may be separated from surrounding structures without cutting, i . e . the bellies of biceps brachii and coracobrachialis muscle were made clearer by loosening the fascia between the two muscles with a blunt probe.
35.
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 : it is strengthened by fibrous aponeuroses, derived from the pectoralis major and latissimus dorsi medially, and from the deltoideus laterally.
36.
The term " biceps brachii " is a Latin phrase meaning " two-headed [ muscle ] of the arm ", in reference to the fact that the muscle consists of two bundles of muscle, each with its own origin, sharing a common insertion point near the elbow joint.
37.
Below this it is thin, and at the upper border of the pectoralis minor it splits into two layers to invest the muscle; from the lower border of the pectoralis minor it is continued downward to join the axillary fascia, and lateralward to join the fascia over the short head of the biceps brachii.
38.
The term, from Latin, for the main upper arm flexor in the singular is the " biceps muscle " ( from " biceps brachii " ); however, many English speakers take it to be a plural and refer to the muscle of only one arm, by back-formation, as " a bicep ".
39.
The " horizontal portion " is flattened from above downward; its upper surface is convex and irregular, and gives attachment to the Pectoralis minor; its under surface is smooth; its medial and lateral borders are rough; the former gives attachment to the conjoined tendon of origin of the Coracobrachialis and short head of the Biceps brachii and gives attachment to the coracoclavicular fascia.
40.
A muscular slip, the axillary arch, varying from 7 to 10 cm in length, and from 5 to 15 mm in breadth, occasionally springs from the upper edge of the latissimus dorsi about the middle of the posterior fold of the axilla, and crosses the axilla in front of the axillary vessels and nerves, to join the under surface of the tendon of the pectoralis major, the coracobrachialis, or the fascia over the biceps brachii.
