Sacrum & Coccyx Flashcards
What part of the sacral ala is derived from the costal element?
Anterior 2/3
The costal element and true transverse process of sacrum unite to form what feature?
Sacral ala
How many fibrous (amphiarthrosis) syndesmosis joint surfaces are present on the first sacral vertebral body?
4
How many joint surfaces are present on the vertebral body of the first sacral segments?
5
What muscle may attach to the first sacral vertebral body?
Psoas major
What is the reported angulation of the first sacral articular facets?
Lie vertically in the coronal plane
What is the position of the sacral zygapophysis in adults?
Lies in the coronal plane for L5/S1
What is the orientation of the first sacral superior articular facet?
Backward, upward, medial (BUM)
Typically concave
What is the name given to the projection on the first sacral superior articular process?
Mammillary process
From the anterior view, the intervertebral discs of sacrum will be replaced by what feature?
Transverse ridges
An imaginary line drawn along the dorsal midline of sacrum is identified as the _____.
Median sacral crest
What forms the median sacal crest
Fused spinous processes and their spinous tubercles
What is the name given to the congenital condition in which the fifth lumbar spinous process i elongated, the sacrum exhibits spina bifida, and dorsiflexion produces pain?
Knife Clasp Syndrome
An imaginary line drawn from the superior articular process of S1 to the sacral cornu will form what feature?
Intermediate sacral crest
What forms the intermediate sacral crest?
Fused articular processes and their facets
What features may be identified along the intermediate sacral crest?
Mammillary process of S1
Sacral cornu of S5
What is the remnant of the inferior articular process and facet of S5?
Sacral cornu
What is the name of the inferior opening of the sacral spinal canal?
Sacral hiatus
What forms the lateral sacral crest?
Fused transverse processes
Transverse tubercles from S1 to S5
What is the sacral tuberosity?
Enlarged transverse tubercle of S2
What is the name of the joint formed by the sacral tuberosity?
Accessory sacro-iliac joint
What muscle is said to attach to the dorsal surface of the sacrum?
Iliacus
What feature is identified on the lateral surface of S1-S3?
Auricular surface
What classification of joint is formed by the auricular surface of sacrum?
Synovial plane (diarthrosis arthrodia)
What feature does the anterior surface of the superior epiphyseal rim of S1 form?
Sacral promontory
What ligament is attached to the sacral hiatus?
Superficial posterior sacrococcygeal ligament
How many synovial joints are typically present at sacrum?
4
What joint classifications are typically present at sacrum?
Fibrous (amphiarthrosis) syndesmosis
Cartilaginous (amphiarthrosis) symphysis
Synovial plane (diarthrosis arthrodia)
What forms the posterior boundary for the fifth sacral spinal nerve intervertebral foramen?
Sacral cornu
Coccygeal cornu
Superficial posterior sacrococcygeal ligament
Intercornual ligament
What forms the anterior boundary for the fifth sacral spinal nerve intervertebral foramen?
Vertebral body S5
vertebral body Co1
Deep posterior sacrococcygeal ligament
Intervertebral disc
What is the homolog for the posterior longitudinal ligament at S5?
Deep posterior sacrococcygeal ligament
What is the homolog for the anterior longitudinal ligament at S5?
Anterior sacrococcygeal ligament
What is the homolog for the ligamentum flavum at S5?
Superficial posterior sacrococcygeal ligament
What forms the inferior boundary for the spinal canal?
Union of the superficial posterior and deep posterior sacrococcygeal ligaments
What ligament is formed by the union of the superficial posterior sacrococcygeal and the deep posterior sacroccygeal ligaments at Co1?
Posterior sacrococcygeal liament
What ligament is the homologof the intertransverse ligament at S5?
Lateral sacrococcygeal ligament
What ligament divides the sciatic foramen into the greater and lesser sciatic foramina?
Sacrospinous ligament
Which ligament has a broad attachment along the lateral margin of sacrum and coccyx and then attaches to the ischial tuberosity?
Sacrotuberous ligament
Which ligament represents a thickening of the fibrous capsule of the sacro-iliac joint?
Anterior sacro-iliac ligament
Which ligament is the strongest of the sacro-iliac ligaments and is penetrated by dorsi rami of the sacral spinal nerves?
Interosseous sacro-iliac ligament
Which ligament will attach the intermediate sacral crest of S1, lateral sacral crest of S2 to the posterior iliac spine?
Short posterior sacro-iliac ligament
Which ligament attaches the lateral sacral crest of S3 and S4 to the posterior superior iliac spine?
Long posterior sacro-iliac ligament
What is the homolog for the capsular ligament at S5?
Intercornual ligament
What is the number of coccygeal somites?
10
What is the typical number of segments that unite to form the adult coccyx?
4 segments
When is ossification of coccyx completed?
About age 30
What is the direction of fusion of coccygeal segments?
From caudal to cranial, the last segments to fuse together are Co1 and Co2
What is the direction of the coccygeal curve?
Posterior (kyphotic)
What is the major motion and range of motion for coccyx?
Flexion - extension
5-20 degrees
How many coccygeal nerves are present in the fetus?
Typically 5 pairs of cocygeal nerves are present
How many coccygeal nerves are present in the adult?
Typically only one pair of coccygeal nerves remain
What forms the coccygeal nerve plexus?
S4, S5 and Co1 nerves
What is the ganglion impar?
A midline sympathetic ganglion
What innervates the coccygeal glomus or coccygeal body?
Both sympathetic and parasympathetic fibers are indentified
What muscles attach to the coccyx?
Ischiococcygeus
Levator ani
What joint classifications are present for coccyx?
Cartilaginous (amphiarthrosis) symphysis
Fibrous (amphiarthrosis) syndesmosis
What forms the posterior boundary for the first coccygeal spinal nerve intervertebral foramen?
Sacral cornu
Coccygeal cornu
Superficial posterior sacrococcygeal ligament
Intercornual ligament
What forms the anterior boundary for the first coccygeal spinal nerve intervertebral foramen?
Vertebral body S5
Vertebral body Co1
Deep posterior sacroccygeal ligament
Intervertebral disc
