Muscles of the Tail are situated around the tail enclosed in the strong coccygeal fascia. These muscles gradually diminish in their thickness as they are traced backwards.
- The movements of the tail are effected by five pairs of coccygeal muscles, three of which are longitudinally disposed around the coccygeal vertebrae and thus cover them completely.
- They are composed of series of fasciculi terminating into tendons.
- The coccygeal muscles are named as follows
- Sacro-coccygeus dorsalis (Erector coccygeus)
- Sacro-coccygeus lateralis (Curvator coccygeus)
- Sacro coccygeus ventralis (Depressor coccygeus)
- Intertransversales caudae
- Coccygeus
- Recto-coccygeus
- Three sacro-coccygeal muscles are distinguished by their position as dorsalis, lateralis and ventralis.
- Sacro-coccygeus dorsalis (Erector coccygeus)
- This muscle is situated on the dorsal aspect of the tail with its fellow on either side of the spines.
- Origin: The last three or four sacral spines and spines of some of the coccygeal vertebrae.
- Insertion: The upper faces of bodies of the coccygeal vertebrae, beyond the third.
- Action: To elevate the tail and to incline it laterally.
- Sacro-coccygeus lateralis (Curvator coccygeus)
- This muscle is situated lateral to the preceding. It is confounded at its anterior extremity with the multifidus dorsi
- Origin: The spinous process of the last lumbar and the transverse process of the sacral and the coccygeal vertebrae.
- Insertion: Lateral faces of the vertebrae, except the first three.
- Action: To elevate the tail and flex it laterally.
- Sacro coccygeus ventralis (Depressor coccygeus)
- This muscle is thicker than the dorsalis and situated on the ventral aspect of the tail. It consists of two parts, medial and lateral.
- Origin: Transverse process of fifth sacral vertebra.
- Insertion: Medial part is inserted to bodies of coccygeal vertebrae. Lateral part is inserted to bodies and transverse processes of coccygeal vertebrae.
- Action: To depress the tail.
- Intertransversales caudae
- These are situated in the lateral face of the tail between the lateralis and ventralis muscle. It extends from one vertebra to another and thus occupies the inter-transverse spaces.
- Origin: The lateral border of the sacrum and the transverse process of preceding coccygeal vertebra.
- Insertion: The transverse process of the first coccygeal and the transverse process of the vertebra behind.
- Coccygeus
- This muscle is thin, triangular situated against the lateral wall of the pelvis between the sacro-sciatic ligament and the rectum.
- Origin: Pelvic surface of the sciatic ligament, near the ischiatic spine.
- Insertion: The transverse processes of the second and third coccygeal vertebrae.
- Recto-coccygeus
- It is large band of plain muscle and detached on either side from the longitudinal layer of the muscular coat of rectum, to the fourth and fifth coccygeal vertebrae
- Action: To compress the anus, depress the tail over the perineum and flex the tail laterally.
- Blood supply: Middle and lateral coccygeal arteries.
- Nerve supply: Coccygeal nerves.
HORSE
- Resemble those of the ox in general.
- The coccygeus is less developed.
DOG
- Resemble those of the ox in general.
- These coccygeal muscles involve in the formation of pelvic diaphragm
- There is an additional sacro-coccygeus which arise on the edge of the sacrum, the transverse process of the first coccygeal vertebra and the posterior border of the ilium.
- The sacro-coccygeus arises from the lumbar vertebrae also.
