- Scapula, coracoid and clavicle, meet to form the foramen triosseum, through which passes the tendon of the supracoracoideus, or subclavius muscle to the tuberculum superius of the humerus.
There is a patella, intercalated in the tendon of the femori-tibialis or extensor cruris muscle.
On the anterior side of the tibia, is the intercondylar sulcus, which is crossed by an oblique bridge of tendon or bone, acting as a pulley for the tendon of the extensor digitorum communis muscle.
The chief muscular mass, arising from the sternum in the shape of a U, is the pectoralis muscle; its fibres converge into a strong tendon, which is inserted upon the greater tubercle and upper crest of the humerus, which it depresses and slightly rotates forwards during the downstroke.
This arises mostly from the angle formed by the keel with the body of the sternum, passes by a strong tendon through the foramen triosseum, and is inserted upon the upper tubercle of the humeral crest, which it rotates and abducts.
Its elastic tendon runs directly to the carpus, forming thereby the outer margin of the anterior patagium, or fold of skin between the upper and forearm, which it serves to extend, together with the propatagialis brevis muscle.
This runs down the anterior and outer side of the upper arm, and is attached to the proximal tendon of the extensor metacarpi radialis longus, a little below the outer condyle of the humerus.
In most birds the tendon is split into several portions, one of which is often attached to the outer side of the ulna, below the elbow joint, while others are in variable but characteristic ways connected with similar slips of the propatagialis longus.
Arising as a long tendon from the sterno-scapular ligament, it passes the axilla by means of a fibrous pulley, accompanies the axillary vessels and nerves along the humerus, and is inserted by a few fleshy fibres on the base of the last two or three cubital quills.
Here, alone, at the distal portion of the tendon, occur muscular fibres, but these are unstriped, belonging to the category of cutaneous muscles.
We have here the interesting fact that a muscle (portion of the triceps humeri of the reptiles) has been reduced to a tendon, which in a secondary way has become connected with cutaneous muscles, which, when strongly developed, represent its belly.
The flexor digitorum sublimis muscle arises fleshy from the long elastic band which extends from the inner humeral condyle along the ventral surface of the ulna to the ulnar carpal bone, over which the tendon runs to insert itself on the radial anterior side of the first phalanx of the second digit.
When typically developed its long tendon passes the knee j oint, turning towards its outer side, and lastly, without being anywhere attached to the knee, it forms one of the heads of the flexor perforates digit, ii.
This, when fully developed, consists of two parts, but inserted by a single ribbon-like tendon upon the hinder surface of the femur, near the end of its first third; the caudal part, femoro-caudalis, expressed by Garrod by the symbol A, arises from transverse processes of the tail; the iliac part (accessorofemoro-caudal of Garrod, with the symbol B), arises mostly from the outer surface of the postacetabular ilium.
One, the quadratus or bursalis muscle, arises from the hinder surface of the eyeball, and forms with its narrow margin, which is directed towards the optic nerve, a pulley for the long tendon of the pyramidalis muscle.
This arises from the nasal surface of the ball, and its tendon passes into the somewhat imperfectly transparent nictitating membrane.
Birds possess an ear-muscle which at least acts as a tensor tympani; it arises near the occipital condyle, passes through a hole into the tympanic cavity, and its tendon is, in various ways, attached to the inside of the membrane and the neighbouring extracolumellar processes.
Tendon of the flexor hallucis longus muscle sending a strong vinculum to that of the flexor profundus muscle, the tendon of which goes to the third toe only.
'14,' sp) L H Externa of coxa O Alary tendon of From Miall and Denny, The Cockroach.
The top bone is the os calcis, or hock bone, to which the tendon Achilles is attached.
The digastric muscles also are remarkable for their well-defined central tendon, and in many species their anterior bellies are united between the two halves of the lower jaw.
It is with the neural element of muscle tonus that tendon phenomena are intimately associated.