Question:hard
A 16 year old girl failed her final examination. Disgusted with life, she cut across the front of her wrist at the flexor retinaculum. She was rushed to hospital, and the surgeon noticed that the cut was superficial. All of the following structures would have been damaged except:
A 16 year old girl failed her final examination. Disgusted with life, she cut across the front of her wrist at the flexor retinaculum. She was rushed to hospital, and the surgeon noticed that the cut was superficial. All of the following structures would have been damaged except:
Show Hint
Ask which of these structures sits deep to the flexor retinaculum inside the carpal tunnel, that one is protected from a superficial cut.
Updated On: Jul 8, 2026
- Ulnar nerve
- Median nerve
- Palmar cutaneous branch of median nerve
- Superficial branch of radial artery
Show Solution
The Correct Option is B
Solution and Explanation
Step 1: Separate deep structures from superficial ones.
Only structures lying above (superficial to) the flexor retinaculum can be cut by a wound the surgeon describes as superficial. Anything travelling inside the carpal tunnel, deep to the retinaculum, is protected.
Step 2: Sort the four options.
The ulnar nerve travels through Guyon's canal, superficial to the retinaculum. The palmar cutaneous branch of the median nerve branches off before the wrist and stays superficial. The superficial branch of the radial artery, as its name says, runs in the superficial plane. All three of these sit in the path of a shallow cut.
Step 3: Look at the median nerve trunk.
The median nerve itself, not its small cutaneous branch, passes through the carpal tunnel beneath the flexor retinaculum along with the flexor tendons. This puts it in the deep plane, out of reach of a superficial wound.
Step 4: Conclude.
Since the wound was superficial, the one structure spared is the median nerve trunk.
\[ \boxed{\text{Median nerve}} \]
Only structures lying above (superficial to) the flexor retinaculum can be cut by a wound the surgeon describes as superficial. Anything travelling inside the carpal tunnel, deep to the retinaculum, is protected.
Step 2: Sort the four options.
The ulnar nerve travels through Guyon's canal, superficial to the retinaculum. The palmar cutaneous branch of the median nerve branches off before the wrist and stays superficial. The superficial branch of the radial artery, as its name says, runs in the superficial plane. All three of these sit in the path of a shallow cut.
Step 3: Look at the median nerve trunk.
The median nerve itself, not its small cutaneous branch, passes through the carpal tunnel beneath the flexor retinaculum along with the flexor tendons. This puts it in the deep plane, out of reach of a superficial wound.
Step 4: Conclude.
Since the wound was superficial, the one structure spared is the median nerve trunk.
\[ \boxed{\text{Median nerve}} \]
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