Which two muscles share an origin that includes the nuchal ligament?

Which two muscles share an origin that includes the nuchal ligament?

• A. Serratus posterior inferior and splenius capitis
• B. Splenius capitis and trapezius
• C. Serratus posterior superior and splenius capitis
• D. Serratus posterior superior and serratus posterior inferior

Answer: (C)

The nuchal ligament is a strong fibrous band running along the back of the neck, and it serves as a proximal attachment for several muscles. The two muscles that share this exact origin are the serratus posterior superior and the splenius capitis. Splenius capitis originates from the lower part of the nuchal ligament and the spinous processes of C7 to T3, then inserts on the mastoid process and the occipital bone near the superior nuchal line. Its action includes extending the head and neck when both sides contract, and aiding in lateral flexion and rotation when one side contracts. Serratus posterior superior also begins from the nuchal ligament, along with the spinous processes of C7 to T3, and inserts on ribs 2 through 4 (sometimes 2–5). Its job is to elevate the upper ribs during inspiration. That shared proximal attachment to the nuchal ligament makes them the best pair for this question. The other options don’t reflect two muscles with that same ligamentous origin: serratus posterior inferior does not originate from the nuchal ligament (it comes from lower thoracic and upper lumbar spines), and while trapezius has extensive neck attachments, the classic, direct shared origin with splenius capitis in this context is not the same nuchal-ligament pairing.

The nuchal ligament is a strong fibrous band running along the back of the neck, and it serves as a proximal attachment for several muscles. The two muscles that share this exact origin are the serratus posterior superior and the splenius capitis.

Splenius capitis originates from the lower part of the nuchal ligament and the spinous processes of C7 to T3, then inserts on the mastoid process and the occipital bone near the superior nuchal line. Its action includes extending the head and neck when both sides contract, and aiding in lateral flexion and rotation when one side contracts.

Serratus posterior superior also begins from the nuchal ligament, along with the spinous processes of C7 to T3, and inserts on ribs 2 through 4 (sometimes 2–5). Its job is to elevate the upper ribs during inspiration.

That shared proximal attachment to the nuchal ligament makes them the best pair for this question. The other options don’t reflect two muscles with that same ligamentous origin: serratus posterior inferior does not originate from the nuchal ligament (it comes from lower thoracic and upper lumbar spines), and while trapezius has extensive neck attachments, the classic, direct shared origin with splenius capitis in this context is not the same nuchal-ligament pairing.